I have a fluval 305 on the 55g sw
tank that i used before going up to the 125g.
The cube has these mods
BioCube 29 Package Deal - Aquarium Filtration Upgrades & Supplies
The light attaches with a magnet so you can light the fuge area which i so far only have cheato and mangroves in, I paln on adding some live rock rubble too. In the media chambers I use chemipure elite, then purigen then a filter pad on top. Here's a picture of the setup from the top view.
Both the fuge and media tray take up the entire center chamber and you cant see it but the far left chamber is empty now. I tried a biocube skimmer but it was garbage. So the flow is directed to a filter pad, then goes down thru the other media and flows into the fuge area and then into the return section.